Simplify the input geometry in base to the value of the indicated threshold. This function is useful when a geometry with less resolution than the original geometry is required. This function uses the algorithm of Douglas-Peucker.

This function can change the topology of the geometry and may result in invalid geometry.

In Postgres, the attribute pg_preserve='y' serves to ensure that the topologie is preserved.

1 geo.simplify

    <geom1 /> *
       <geo.simplify threshold='0.006'>
       <geo.simplify  tol='0.004' pg_preserve='y' threshold='0.006'>
    <from table='buildings' alias='a' >
    <where> = 'MACBA'